Determine the mutagenic activity of 85 selected compounds towards three strains of bacteria. Determine the zone in inhibition of a polymerase A-deficient strain of E. coli in vitro caoused by the 85 compounds. Included two tested strains of Salmonella both in vitro and in vivo in mice (using the host mediated bioassay) to determine the mutagenic activity of the 85 compounds. Initial experiments with the Salmonella shall be performed with strains of TA1530 and TA1535. If either proves inadequate, it will be replaced by another strain of Salmonella following consultation with the project officer. Determine in collaboration with the project officer by literature survey and by direct experimentation the maximally tolerated dose of 1/2 the 85 compounds in mice.